SPECIFICITY AND SENSITIVITY OF EXERCISE-INDUCED ST SEGMENT ELEVATION FOR DETECTION OF RESIDUAL VIABILITY - COMPARISON WITH FLUORODEOXYGLUCOSE AND POSITRON EMISSION TOMOGRAPHY

Objectives. We evaluated the sensitivity and specificity of exercise i nduced ST segment elevation for the detection of residual myocardial v iability. Background. Assessment of residual viability after myocardia l infarction is relevant for establishing indication for revasculariza tion. We have previously shown that exercise-induced ST segment elevat ion is a marker of residual viability. Methods. We studied 34 patients ,vith a previous Q wave myocardial infarction (anterior in 21, inferio r in 13) of whom 18 (group A) had exercise-induced ST segment elevatio n in more than one lead (mean [+/-SD] 1.8 +/- 0.9 mm, range 1 to 4) an d 16 (group B) did not. All patients underwent rest technetium-99m met hoxyisobutyl isonitrile single-photon emission computed tomography (SP ECT), fluorine-18 (F-18) fluorodeoxyglucose positron emission tomograp hy and coronary angiography. The time elapsed between the infarction a nd the viability study was 72 +/- 108 days (range 15 to 400) in group A and 516 +/- 545 days (range 14 to 1,800) in group B. Results. The pr esence and site of previous infarction were confirmed by SPECT studies in all 34 patients. Uptake of F-18 fluorodeoxyglucose within the infa rcted area was present in 18 of 18 patients in group A but in only 9 ( 56%) of 16 in group B (p < 0.01). In patients with an anterior infarct ion, the sensitivity, specificity and predictive accuracy of exercise- induced ST segment elevation for detection of residual viability were 82%, 100% and 86%, respectively (95% confidence intervals 46% to 83.5% , 59% to 100% and 55.6% to 87.1%, respectively). Conclusions. Exercise -induced ST segment elevation in infarct-related leads has a high spec ificity and acceptable sensitivity for detection of residual viability within the infarcted area.